A processing solution and method for making a lithographic offset plate by the silver salt diffusion transfer process.

摘要

The present invention provides an alkaline processing solution comprising at least one silver halide solvent other than sulfite, characterized in that said alkaline processing solution further contains aluminium ions in an amount of at least 0.3 g/l. There is further provided a method for making a lithographic printing plate according to the DTR-process using an aqueous alkaline processing solution in the presence of at least one developing agent and at least one silver halide solvent, characterized in that said alkaline processing solution contains aluminium ions in an amount of at least 0.3 g/l.